PROJECT SUMMARY With a national prevalence estimate of 3.9 per 100,000 people, amyotrophic lateral sclerosis (ALS) is one of the most common disabling neuromuscular diseases among adults in the United States. Eighty-five percent of persons with ALS demonstrate swallowing impairment (dysphagia) over the course of the disease (Carpenter, McDonald, & Howard, 1978; Chen & Garrett, 2005). Despite the significant impact that the loss of swallowing function has in persons with ALS ( Fattori et al., 2006) for a variety of reasons, including the variability of , disease progression from person to person, the inconsistency of symptom onset, and the lack of sensitivity to small amounts of change found in currently used outcome measures, predicting symptom progression over the course of the disease is difficult (Rutkove et al., 2007). As a result, clinical management of dysphagia in this population is a significant challenge. Therefore, there is a great need for research directed at improving biomarkers of swallowing decline. In the proposed research, we will investigate the relation between anatomic and biomechanic markers of the tongue and changes in swallow physiology, swallow severity, and swallow safety in persons with ALS. In AIM 1, we will correlate anatomic measures of the tongue using electrical impedance myography (EIM) with measures of swallow physiology, severity, and safety. Additionally, we will use electrical impedance myography (EIM) to determine whether changes in lingual muscle tissue health are present in persons with ALS who are pre-symptomatic of bulbar impairment. Prior research on EIM, as well as preliminary data in our lab, suggests that lingual EIM will be sensitive to the disease process prior to symptom onset and over the course of the disease process. In Aim 2, we will correlate biomechanic measures of the tongue (speed, range of motion, and coordination) during the swallow with measures of swallow physiology, swallow severity, and swallow safety. Our preliminary data suggests that lingual range of motion during the swallow is highly correlated with swallow function. The overall goal of the proposed research is to improve biomarkers of swallow impairment, which will significantly improve clinical management of dysphagia for persons with ALS. Results of this research will allow for improved prognostic capabilities and improved ability to implement physiologically based therapeutic techniques aimed at prolonging swallow function.